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{Summer Fun List} Diet Coke – Mentos Geyser

At the beginning of the summer my kids and I brainstormed some fun things we could do over our “staycation” this summer. I needed some ideas up my sleeve for those times when we were around the house and everyone was starting to get nudgy and bothersome (my kids are masters at bothering each other….isn’t that the job of a sibling?)

The kids and I thought we’d share the pros and cons some of our summer amusements in case you’re thinking of trying them.

First up…..
The Diet Coke – Mentos Geyser
Have you heard of this little experiment? The Mentos cause the carbon dioxide gas (the soda carbonation) to escape. Whether or not this is a chemical or physical reaction is under debate by scientists, and you can read about what happens in this experiment at one of my favorite kid sites, Steve Spangler Science. Apparently this experiment will work with non-diet soda but the diet version creates a less sticky explosion.

How To:
Buy a two-liter bottle of Diet Coke and a pack of Mentos mints. (I bought two of both.)

If you want to get a picture of this, put your camera on the right setting and set it away from the experiment before you get started! (I clearly didn’t set my camera first because my action shots are blurry.)  This would be fun to video too! Oh – and if you have a dog – make sure to keep him in the house until you’re done with your explosion because he’ll be drawn to that bottle of Diet Coke like a moth to a flame (speaking from experience here!!)

Set the bottle in the middle of your yard or a field, in a flat spot. Open the bottle and the Mentos, and all at once, slide all of the Mentos into the bottle. (I tried this using a rolled piece of paper as the Steve Spangler site suggests, but Hannah had more luck putting them into a bottle directly from the package.)

It’s important to know ahead of time that the entire package of Mentos need to go in all at once because you only get one explosion out of each 2 liter bottle – and the more Mentos that you get in there, the bigger the geyser will be. The geyser happens almost immediately so a swift motion of depositing the Mentos into the Diet Coke (and jumping out of the way!) is necessary.

If you drop the Mentos into the bottle properly, the Diet Coke will shoot up in the air several feet.

The kids tried to catch the Diet Coke in cups (and directly into the their mouths!).

(I usually don’t have soda in the house because my little sugar fiends would drink it all day long if they could, so catching the soda and drinking it was an added bonus!)

Pros:  kids of all ages think this is awesome /// for about 5 minutes you’re the coolest mom ever /// there is actually something to be learned about chemical and physical reactions
Cons:  the whole shebang takes about 5 minutes beginning to end /// for the length of time this activity amuses your kids there’s not a lot of bang for the buck as far as mom is concerned (about $7 for two geysers)
Worth The Time/Effort/Money?:  Mom – yes (once!), Kids – yes!!!

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Friday 20th of July 2012

I am so doing this with the kids this weekend! We needed a cool experiment to fight off the summer doldrums...


Jessamie Vincent

Thursday 19th of July 2012

You are one very cool momma! G is still at the age she would just shake her head no and say "that's too loud, mommy" haha

Jennifer L. Griffin

Wednesday 18th of July 2012

This is always a popular youth group stunt at our church! I need something fun to do with the kids tomorrow...they'll love this!

Dana Frieling

Tuesday 17th of July 2012

Okay, you just talked me into it. My son would go crazy for this type of fun. Thanks (I think)!


Tuesday 17th of July 2012

The look on your son's face in the first gyser pic is priceless. We did this on the 4th of July with a bunch of neighbors...usually we do fireworks, but we are under a fire ban. The mentos gysers were the next best thing and the kids loved them. I definitely need some more of these ideas because summer is starting to get a bit loooooong and the TV has been on way too much lately.